1. Field of the Invention
In general, this particular invention relates to the forging of metal articles having predetermined shapes. More specifically, however, the present invention relates to a novel and improved method of forging preselected recessed configurations in a body member by forging a slave preform and the body member, and quenching such slave preform after the forging to facilitate removal thereof.
2. Brief Description of the Prior Art
Present day forging methods are unable to satisfactorily forge either internally or externally constructed generally radial recesses on members, such as the type found on inner bearing cone members, or other conventional inner and outer bearing race members. It has been determined that the difficulty encountered in the formation of such recesses was due to conventional forging techniques. In particular, the external or internal recesses would lock on the die wall or core rod wall, respectively. Various techniques exist, however, in industry for forming such recesses. One standard approach for use in the formation of such bearing cones and races includes conventional machining steps of appropriate metal blanks so as to correspondingly form a continuously smooth and recessed surface. While this particular practice has been followed, it nevertheless prevents several significant shortcomings. For instance, one substantial drawback associated with machining is that it inevitably results in additional costs. These cost increases include not only that which results from high scrap rates, but also the additional heat treatment necessary following machining in order to obtain the necessary case hardness and case depth.
Moreover, it should be pointed that the the field of forming bearing components is competitive and there is somewhat of a narrow or small profit margin associated with the production of such bearing elements. As a consequence thereof, it will, of course, be appreciated that even slight savings in cost render such bearing components more desirable from a cost standpoint.
From the preceding considerations, it is quite apparent that the formation of external or internal recesses on these bearing components, especially of the powdered metal type using the conventional machining approach, is complicated and are relatively higher in cost as well as require added time and labor.
For the reasons enumerated above, it is difficult and time-consuming to accurately form each bearing component. The prior art is absent a reliable and accurate technique enabling the formation of conventional bearing components without the noted drawbacks.
Additionally, the state of the art is absent not only processes enabling even more economical manufacture of large numbers of inner or outer bearing race elements having continuously smooth recessed surfaces, but also enabling the surfaces of case hardened powdered metal bearing parts to be formed in a manner without impairing the protection provided by case hardening.